Field of the Invention
The present invention relates to a technique for case sharing of a power semiconductor module.
Description of the Background Art
Power Semiconductor modules include base plates, insulating substrates on the base plates, semiconductor chips on the insulating substrates, and cases that accommodate them.
Semiconductor chips have different mounting areas depending on their different current capacities. That is, semiconductor chips with large current capacities have large mounting areas, and semiconductor chips with small current capacities have small mounting areas. Moreover, the base plates serve to dissipate heat generated from the semiconductor chips. Accordingly, in the power semiconductor modules that use the semiconductor chips with the small current capacities and small mounting areas, it is possible to reduce the areas of the base plates as well in terms of heat dissipation capability. This reduces materials for the base plates.
Unfortunately, changing the sizes of the cases in conformance with the areas of the base plates increases kinds of cases, thus resulting in decreased productivity of the cases.
Accordingly, to use cases (packages) of a uniform size for base plates of various sizes, proposed is a method for disposing spacers between the base plates and the cases (For instance, Japanese Patent Application Laid-Open No. 06-188363).
In a power semiconductor module in Japanese Patent Application Laid-Open No. 06-188363, a side surface of a base plate and a side surface of a spacer are bonded with an adhesive. Hence, the bond strength thereof is disadvantageously week.